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LASIMP - Research project

Femtosecond LASer for dental IMPlants multifunctional texturing

PhD student: Steve PAPA, ED 488 SIS (Science, Engineering, Health)

ABSTRACT

Our goal is to use a single/versatile tool, the femtosecond laser, to texture each part of a titanium based dental implant to provide the best functionalities at the desired location. We will select the best anti-bacterial nanotextures for the top of the prosthesis and pro-adhesive texturing for the interface with gingival tissues.
Original approaches: we will assess anti-bacterial properties using bacteria from oral microbiota associated with periodontitis/peri-implantitis (S. mutans, P. gingivalis …). We will quantitatively test cell adhesion of fibroblasts using scratches tests by way of indenter (LTDS) and we aim to develop models of infection for advanced clinical evaluation of implants and prosthesis.
Multi-scale texturing created by the ultrafast laser will be used to obtain multiple functionalities at implant surfaces, being both non-adhesive for bacteria and pro-adhesive for gingival cells.
 
  • LASIMP_illus_figure 2
    Antibacterial texturing: Streptoptocus mutans (green) on polished and nano-textured surface (fig2) © LTDS/SAINBIOSE
    LASIMP_illus_figure 2
  • LASIMP_illus_figure 4
    hMSC short term adhesion: hMSC stained (nuclei, actin cytoskeleton, vinculin) for fluorescence microscopy, to observe focal adhesion at early time (48h) on polished or laser textured areas (fig4) © SAINBIOSE/UJM
    LASIMP_illus_figure 4
  • LASIMP_illus_figure 5
    Pro-adhesive texturing for gingival fibroblasts: scratch test to measure cell layer adhesion on texturing (fig5) © SAINBIOSE/UJM
    LASIMP_illus_figure 5
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    Laser textured TOPOCHIP: SEM images of micro/nanostructures obtained by femtosecond laser texturing of titanium plates (fig1) © ENISE/ECL/LTDS
    LASIMP_illus_figure1
  • LASIMP_illus_figure3
    LASIMP_Streptococcus mutans adhesion: SEM imaging of S. mutans over laser-induced Periodic Surface Structures with different pattern periodocities (fig3) © ENISE/ECL/LTDS
    LASIMP_illus_figure3
  • LASIMP_illus_publi2023
    LASIMP project - Publication - Scientific Reports 13 - Sept 2023 © Steve Papa (UJM)
    LASIMP_illus_publi2023
  • LASIMP_publi1
    Inscription setup and the scanning direction employed for texturization © Steve PAPA / SAINBIOSE lab
    LASIMP_publi1
  • LASIMP_soutenance_steve
    Sedao (LabHC), Alain Guignandon (Sainbiose), Steve Papa (Sainbiose) and Virginie Dumas (LTDS), December 21, 2023. © UJM
    LASIMP_soutenance_steve
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RESULTS

To assess the biological performance of texturing produced by femtosecond laser, topochips containing a multitude of different nanostructures were manufactured by the Hubert Curien laboratory and Manutech-USD. Several laser sources (1030nm, 515nm and 257nm) and several laser parameters (beam power, fluence, number of pulses, polarization) were tested. The nanostructures obtained were characterized by Scanning Electron Microscopy (SEM). 
Streptococcus mutans, a bacterium involved in peri-implantitis, was seeded on the topochips and labeled with calcein to evaluate the properties of each texturing. This preliminary screening showed that, in accordance with the literature, the correlation between pattern periodicity and bacteria size, is directly linked to bacterial ability to adhere on titanium surfaces (Figure 2). Bacteria and topographies interactions are also observed by SEM, confirming that when pattern periodicity is inferior to bacteria size, contact surfaces between titanium and bacteria are reduced, and so is the bacterial adhesion (Figure 3).
To assess short-term cell adhesion, fluorescence microscopy was used to analyze the formation and localization of focal contacts on different areas. At 48 hours, human mesenchymal stem cells (hMSCs) have formed larger focal contacts on polished surfaces compared to textured surfaces (Figure 4). However, in the longer term (28 days of culture), scratch tests on cell layer, developed by the LTDS, have shown that the adhesion of the cell layer is better on the areas textured with the femtosecond laser (Figure 5). These adhesion tests were developed on hMSCs, and similar tests are now carried out on gingival fibroblasts. Since one of the major problems of peri-implantitis is the lack of adhesion of the gingival tissues to the implant, which leads to bacterial infiltration, an improved fibroblasts adhesion will be a key to increase implant lifetime.
 

PUBLICATIONS

CONFERENCES
  • X. Sedao, S. Papa, M. Maalouf, Y. Di Maio, A. Abou Khalil, H. Hamzeh-Cognasse, M. Thomas, A. Guignandon, V. Dumas, Ultrafast laser functionalization of dental implants: influence of wavelength and polarization on tissues adhesion and bacterial repellency, SPIE, San Francisco, United States, 2023
  • Y. Di Maio, G. Aubert, A.P. Hamri, X. Sedao, M. Maalouf, M. Muck, D. Pallarés-Aldeiturriaga, J. Garnier, S. Papa, V. Dumas, A. Guignandon, J. Heitz, N. Compère, From research to industry: transferring bioactive laser treated surfaces to the production of biomedical screws, SPIE, San Francisco, United States, 2023
  • Papa S., Maalouf M., Thomas M., Eyraud MA., Cognasse H., Claudel P., Di Maio Y., Sedao X, , Guignandon A. & Dumas V. Femtosecond lasers Fonctionalised titanium surfaces For dental implants application. 32nd Annual Conference of the European Society for Biomaterials (ESB) Bordeaux, Septembre 2022
  • Steve Papa, Mathieu Maalouf, Alain Abou Khalil, Xxx Sedao, Pierre Claudel, Nicolas Compère, Alain Guignandon, and Virginie Dumas, Femtosecond lasers structured titanium implant in regulating bacteria and bone stem cell adhesion. Society of Photo-Optical Instrumentation Engineers (SPIE) Proc. SPIE PC11942, Lasers in Dentistry XXVIII, PC1194205 (7 March 2022)
  • Papa S., Thomas M., Eyraud MA., Cognasse H., Claudel P., Abou-Khalil A., Sedao X, Guignandon A. & Dumas V. Femtosecond lasers structured titanium dental implants in regulating bacterial adhesion. Congrès BIOMAT 2021: 19-22 octobre 2021 Bourg Saint Maurice